Psychological terror, far more than physical, is central to Edgar Allan Poe's writings, including "The Pit and the Pendulum." Whether the imagined audible beating of "The Tell Tale Heart" or this example of psychological terror from his poem "A Dream Within A Dream":
"I stand amid the roar/Of a surf-tormented shore,/And I hold within my hand/Grains of the golden sand/How few! yet how they creep/Through my fingers to the deep/While I weep -- while I weep!"
Or, consider this line from "The Black Cat":
"Mad indeed would I be to expet it, in a case where my senses reject their own evidence. Yet, mad am I not..."
Poe's work is replete with examples of psychological terror. In the case of "The Pit and the Pendulum," the psychological torment of the protagonist. The "pendulum" referred to in the title, of course, is a medieval torture device employing a large swinging pendulum that, as it swings back and forth, gradually descends until cutting in half the torso of the poor soul strapped to a table beneath it. There is no question that the image of a person being mutilitated is horrifying enough, but Poe grasped that the greatest suspense was in anticipation of the act.
In the "The Pit and the Pendulum," the mental dread is introduced immediately:
"I was sick -- sick unto death with that long agony; and when they at length unbound me, and I was permitted to sit, I felt that my senses were leaving me. The sentence -- the dread sentence of death -- was the last distinct accentuation which reached my ears."
The symbolism of the pendulum is present early in the story. With the image of the torture device already firmly established, here is how the protagonist describes a room into which he enters:
"...there stood against the western wall, a gigantic clock of ebony. It's pendulum swung to and fro with a dull, heavy monotonous clang; and when the minute-hand made the circuit of the face, and the hour was to be stricken, there came from the brazen lungs of the clock a sound which was clear and loud and deep and exceedingly musical."
The pendulum of the clock clearly serves as a metaphor for the one in the dungeon, a theme repeated when describing the protagonist's current predicament:
"Looking upward, I surveyed the ceiling of my prison...It was the painted figure of Time as he is commonly represented, save that, in lieu of a scythe, he held what, at a casual glance, I supposed to be the pictured image of a huge pendulum such as we see on antique clocks."
This time, the pendulum was, in fact, the large one used to tortue and mutilate.
Poe understood that it took a moment to kill; the dreaded anticipation of an act of violence can be prolonged and amplified. One can logically conclude, therefore, that in "The Pit and the Pendulum," psychological horror takes precedence over physical horror.